Device for treating freshly coated cathode ray tube blanks



R. J. SCHENK June 25, 1957 DEVICE FOR TREATING FRESHLY COATED CATHODE RAY TUBE BLANKS Filed March 26, 1956 INVENTOR. ROBERT JAMESSCHE/VK A TTORNEYS United States Patnt F'atented June 25, 1957 DEVICE FOR TREATING SHLY (HEATED CATHODE RAY TUBE BLANK Robert James Schenk, Pompton Plains, N. J., assignor to Allen B. Du Mont Laboratories, Inc, Ciitton, N. 3., a corporation of Delaware Application March 26, 1956, Serial No. 575,755

2 Claims. (Cl, S 3 21) This invention relates to aeration, and in particular to the introduction of air into a container for the purpose of reducing a partial vacuum and/ or preventing dehydration.

In the manufacture of metallized cathode ray tubes, it is necessary to form on the inner surface of the faceplate, a smooth base layer on which a metal, such as aluminum, may be deposited. One method of producing a smooth base layer is to spray a suitable material, such as Lucite, on the inner surface of the faceplate, invert the tube blank, and permit the excess to drain out through the tube mouth. During the open air draining operation, cool, dry air enters the blank and produces eddy currents, and the Lucite tends to dry out unevenly, resulting in a base layer that is wrinkled, or non-uniform in some other respect. To avoid this possibility, the open end of the inverted tube is immersed in water, thus maintaining a stable condition within the tube and promoting a uniform base layer.

During the draining operation the vapors condense, the excess dripping into the water. This combination of events produces a partial vacuum in the tube, thus drawing water up into the tube neck to a level above that in the surrounding basin. When the tube blank is lifted out of the water an extreme bubbling and splashing is produced within the tube, and this produces a sp'lotched base layer which is unsuitable for the deposition of the aluminum reflecting film.

It is an object of my invention to provide an apparatus and method to avoid the impairment of the base layer.

It is another object of my invention to introduce moist air into the inverted tube to promote slow, even drying of the Lucite.

It is a further object of my invention to permit the reduction of the vacuum in order to facilitate removal of the tube.

The attainment of these objects and others will be realized from the following specification, taken in conjunction with the drawing, which illustrates the basic concept of my invention.

The instant invention contemplates a water basin having positioned within it an air discharge device which permits air to bubble up through the water and into the mouth of an inverted container.

Referring now to the drawing, there is illustrated a conveyor system 10 (which is used merely for illustrative purposes, many forms of this device being known), a tube holder 12 having two jaws which support an inverted tube blank 14 whose inside surface, and particularly faceplate 15, has been sprayed with Lucite, the excess of which it is desired to drain ofi. The configuration of conveyor 10 permits the mouth of the tube to dip below the surface of the water contained in trough 16. An air pipe 18 extends longitudinally along the base of trough 16, and perforations in pipe 18 permit the escape of air, which bubbles upward to the surface of the water, some bubbles finding their way into the mouth of the tube as it is moved along the length of the trough. As the bubbles enter the inverted tube, they accumulate in the bulb portion and gradually expel all the included water until the tube is entirely full of moist air; the air-water boundary being established at the mouth of the tube.

In this way, the tube is maintained full of moist air, and the Lucite on the faceplate l5 dries slowly and evenly as the excess drains off the sides of tube blank 14. In addition, the tube blank may now be readily removed from the water without the splashing previously encountered.

Having described the principles and one embodiment of my invention, I desire to be limited only by the following claims.

What is claimed is:

1. Apparatus for introducing moist air into inverted cathode ray tube blanks, comprising: a water trough; and means to position said blank with its mouth in said trough and under water; air-discharging means below said month said means comprising a pipe positioned longitudinally in said trough, said pipe having perforations along the length thereof; and means to move said blank along said pipe.

2. In the manufacture of cathode ray tubes having a freshly coated faceplate and being under a partial vacuum, the operations of: suspending an inverted cathode ray tube blank on a moving conveyor; immersing the mouth of said blank into a water trough, whereby said partial vacuum partly fill-s said blank with water; and bubbling air through said water into said mouth as the blank is moved along said trough by said conveyor, whereby the upwardly bubbling air will cooperate with the tube to displace the water and aid in the 'drying of said coating.

References Cited in the file of this patent UNlTED STATES PATENTS Lindsay Dec. 6, 1955 OTHER REFERENCES 

